/**
 * This pagination plug-in provides a `dt-tag select` menu with the list of the page
 * numbers that are available for viewing.
 *
 *  @name Select list
 *  @summary Show a `dt-tag select` list of pages the user can pick from.
 *  @author _jneilliii_
 *
 *  @example
 *    $(document).ready(function() {
 *        $('#example').dataTable( {
 *            "sPaginationType": "listbox"
 *        } );
 *    } );
 */

$.fn.dataTableExt.oPagination.listbox = {
    /*
     * Function: oPagination.listbox.fnInit
     * Purpose:  Initalise dom elements required for pagination with listbox input
     * Returns:  -
     * Inputs:   object:oSettings - dataTables settings object
     *             node:nPaging - the DIV which contains this pagination control
     *             function:fnCallbackDraw - draw function which must be called on update
     */
    "fnInit": function (oSettings, nPaging, fnCallbackDraw) {
        var nInput = document.createElement('select');
        var nPage = document.createElement('span');
        var nOf = document.createElement('span');

        var nFirst = document.createElement( 'span' );
        var nPrevious = document.createElement( 'span' );
        var nNext = document.createElement( 'span' );
        var nLast = document.createElement( 'span' );

        nFirst.appendChild( document.createTextNode( oSettings.oLanguage.oPaginate.sFirst ) );
        nPrevious.appendChild( document.createTextNode( oSettings.oLanguage.oPaginate.sPrevious ) );
        nNext.appendChild( document.createTextNode( oSettings.oLanguage.oPaginate.sNext ) );
        nLast.appendChild( document.createTextNode( oSettings.oLanguage.oPaginate.sLast ) );

        nFirst.className = "paginate_button first";
        nPrevious.className = "paginate_button previous";
        nNext.className="paginate_button next";
        nLast.className = "paginate_button last";

        nOf.className = "paginate_of";
        nPage.className = "paginate_page";
        if (oSettings.sTableId !== '') {
            nPaging.setAttribute('id', oSettings.sTableId + '_paginate');
        }
        nInput.style.display = "inline";
        nPage.innerHTML = "当前第 ";
        nPaging.appendChild(nPage);
        nPaging.appendChild(nInput);
        nPaging.appendChild(nOf);

        nPaging.appendChild( nFirst );
        nPaging.appendChild( nPrevious );
        nPaging.appendChild( nNext );
        nPaging.appendChild( nLast );

        $(nInput).change(function (e) { // Set DataTables page property and redraw the grid on listbox change event.
            window.scroll(0,0); //scroll to top of page
            if (this.value === "" || this.value.match(/[^0-9]/)) { /* Nothing entered or non-numeric character */
                return;
            }
            var iNewStart = oSettings._iDisplayLength * (this.value - 1);
            if (iNewStart > oSettings.fnRecordsDisplay()) { /* Display overrun */
                oSettings._iDisplayStart = (Math.ceil((oSettings.fnRecordsDisplay() - 1) / oSettings._iDisplayLength) - 1) * oSettings._iDisplayLength;
                fnCallbackDraw(oSettings);
                return;
            }
            oSettings._iDisplayStart = iNewStart;
            fnCallbackDraw(oSettings);
        }); /* Take the brutal approach to cancelling text selection */
        $('span', nPaging).bind('mousedown', function () {
            return false;
        });
        $('span', nPaging).bind('selectstart', function () {
            return false;
        });

        $(nFirst).click( function () {
            oSettings.oApi._fnPageChange( oSettings, "first" );
            fnCallbackDraw( oSettings );
        } );

        $(nPrevious).click( function() {
            oSettings.oApi._fnPageChange( oSettings, "previous" );
            fnCallbackDraw( oSettings );
        } );

        $(nNext).click( function() {
            oSettings.oApi._fnPageChange( oSettings, "next" );
            fnCallbackDraw( oSettings );
        } );

        $(nLast).click( function() {
            oSettings.oApi._fnPageChange( oSettings, "last" );
            fnCallbackDraw( oSettings );
        } );

        /* Disallow text selection */
        $(nFirst).bind( 'selectstart', function () { return false; } );
        $(nPrevious).bind( 'selectstart', function () { return false; } );
        $(nNext).bind( 'selectstart', function () { return false; } );
        $(nLast).bind( 'selectstart', function () { return false; } );
    },

    /*
     * Function: oPagination.listbox.fnUpdate
     * Purpose:  Update the listbox element
     * Returns:  -
     * Inputs:   object:oSettings - dataTables settings object
     *             function:fnCallbackDraw - draw function which must be called on update
     */
    "fnUpdate": function (oSettings, fnCallbackDraw) {
        if (!oSettings.aanFeatures.p) {
            return;
        }
        var iPages = Math.ceil((oSettings.fnRecordsDisplay()) / oSettings._iDisplayLength);
        var iCurrentPage = Math.ceil(oSettings._iDisplayStart / oSettings._iDisplayLength) + 1; /* Loop over each instance of the pager */
        var an = oSettings.aanFeatures.p;
        for (var i = 0, iLen = an.length; i < iLen; i++) {
            var spans = an[i].getElementsByTagName('span');
            var inputs = an[i].getElementsByTagName('select');
            var elSel = inputs[0];
            if(elSel.options.length != iPages) {
                elSel.options.length = 0; //clear the listbox contents
                for (var j = 0; j < iPages; j++) { //add the pages
                    var oOption = document.createElement('option');
                    oOption.text = j + 1;
                    oOption.value = j + 1;
                    try {
                        elSel.add(oOption, null); // standards compliant; doesn't work in IE
                    } catch (ex) {
                        elSel.add(oOption); // IE only
                    }
                }
                spans[1].innerHTML = "页&nbsp;共" + iPages + "页&nbsp;&nbsp;";
            }
            elSel.value = iCurrentPage;

            var buttons = an[i].getElementsByTagName('span');
            if ( oSettings._iDisplayStart === 0 ) {
                buttons[0].className = "paginate_disabled_previous";
                buttons[1].className = "paginate_disabled_previous";
            } else {
                buttons[0].className = "paginate_enabled_previous";
                buttons[1].className = "paginate_enabled_previous";
            }

            if ( oSettings.fnDisplayEnd() == oSettings.fnRecordsDisplay() ) {
                buttons[2].className = "paginate_disabled_next";
                buttons[3].className = "paginate_disabled_next";
            } else {
                buttons[2].className = "paginate_enabled_next";
                buttons[3].className = "paginate_enabled_next";
            }
        }
    }
};